RAPAPORT... A blue diamond ring estimated at $9 million to $12 million will go under the hammer at Sotheby’s Geneva auction on November 15 alongside a roster of rare colored diamonds.

The rectangular-cut, 5.04-carat, fancy-vivid-blue piece is one of three blue diamonds set to feature at the Magnificent Jewels and Noble Jewels sale. The auction will also include earrings containing a 2.61-carat and a 3.06-carat diamond with a presale estimate of $8 million to $10 million. A brilliant-cut, 2.02-carat, fancy-intense-blue, internally flawless diamond valued at $2 million to $3 million rounds out the set.

Sotheby’s will also offer a cushion-cut, 21.19-carat, fancy-light-pink, type IIa diamond estimated at $4.5 million to $6.5 million, and a collection of white diamonds. Those include a pear-shaped, 40.18-carat, D-color stone with a presale estimate of $2.5 million to $3.5 million, and a Harry Winston necklace with nine D-color, internally flawless diamonds valued at $4.8 million to $5.8 million.

Colored gemstones and signed jewels by Cartier, Bulgari and Van Cleef & Arpels will also be up for sale.

Sotheby’s will preview the jewels from November 10 to 14 at the Mandarin Oriental hotel in Geneva ahead of the auction.